Corrosion and cracking can present concerns for structures used in aircraft and other aerospace vehicles. In particular, corrosion and cracking can have a significant impact on vehicle maintenance costs and ultimately on continued vehicle operation. Therefore, aerospace vehicle owners and operators spend considerable effort identifying and controlling the growth of structural defects. In some cases, the defects may not be visible by direct inspection, and may only be discovered after a relatively time-consuming structural disassembly has taken place.
Thus, there is a need for a relatively inexpensive sensor and supporting system that can be used to monitor material defects in aircraft and other aerospace vehicle structures, and most notably in hard to reach places. This would allow aircraft owners and operators to detect emerging defects in a much more timely, reliable, and cost-efficient manner. It would also be advantageous if such as system could be well characterized in terms of probability of detection (POD) and probability of false indications (PFI).